Method for a secure information transfer

ABSTRACT

The method serves for a secure information transfer between a user device (C) and a central computer (S-D), arranged in a closed network. A connection request is signalled to a second computer (R-Q), not arranged in the closed network, from the user device (C), using the central computer (S-D). The second computer (S-Q) then transmits a message (TAN 1 )—containing an identification (SessionID) to a third computer (S-Z), arranged in the private network. The third computer (S-Z) stores the identification (Session ID) and transmits a verification report (TAN 2 ) containing an access address (URL) for the central computer (S-D) to the second computer (S-Q), which forwards the verification report (TAN 2 ) to the user device (C). The user device (C) then initialises a connection to the central computer (S-D), using the access address (URL), whereby the connection is only accepted by the central computer (S-D) n those cases where the access can be authorised by the stored identification (SessionID).

[0001] The present invention relates to a method for a secure information transfer between two terminals in accordance with the precharacterizing clause of patent claim 1.

[0002] As a result of an increasingly global alignment of companies telecommunication services are increasingly being used to transfer voice and data. The result of this is that the costs caused by these telecommunication services are constantly rising and are becoming a significant cost factor for the companies which are looking for opportunities to reduce these costs. Local and global computer networks such as an ‘Intranet’ or the ‘Internet’ provide an option of transferring data cheaply and all around the world.

[0003] For access to data or services—for example to a server or to an application made available by the server—of a first unit—for example a Company A—originating from a second unit—for example a Company B—or originating from a public access—for example from the ‘Internet’—it is important to prevent unauthorized access to data or services of the unit. This can be done by an access authorization check performed prior to the data access. With an authorization check it is necessary for there to be authorization administration in the first unit to administer the access rights of the individual users. The disadvantage of this type of authorization check is that the access rights for the external users to the first unit must be notified (danger of misuse) and that a user must re-register independently in each case before a data access. Furthermore the authorization administration must be updated on an ongoing basis which involves great administrative expense.

[0004] For secure data access originating from a second unit—for example originating from a user device in an Intranet of Company B—there is also the option of routing the access via an existing transmission facility existing between the units. A transmission device in this sense is for example a fixed connection—that is a physical line connection set up especially for the purpose—or a logical connection—also referred to as a Virtual Private Network, or VPN for short in literature. Alternatively a representative device—also known in literature as a proxy—can be defined in the second unit, via which accesses to the first unit or to a server of the first unit will be undertaken.

[0005] The disadvantage of these solutions is however that a data access to the first unit must always be routed via the fixed connection or that the data access must always take place via the proxy.

[0006] The object of the present invention is to specify an alternate procedure through which there can be secure external access to data or services of a self-contained unit.

[0007] The object is achieved on the basis of the precharacterizing clause of patent claim 1 through its identifying features.

[0008] A significant advantage of the method in accordance with the invention is that the method can be implemented in existing systems with only a small amount of effort.

[0009] A further advantage of the method in accordance with the invention is that no information about the individual authorized external users has to be stored in the first unit. This means that the burden of administration in the unit can be greatly reduced. Advantageous exemplary embodiments of the invention are specified in the subclaims.

[0010] One advantage of the embodiments of the invention defined in the subclaims is in the use of the HTTPS protocol (HTTPS: HyperText Transport Protocol Secure) for data transmission between the individual units involved in the method in accordance with the invention and in additional encryption of the data to be transmitted—for example via the familiar PGP procedure (PGP: Pretty Good Privacy)—in that with transmission via a public network an unauthorized data access to the transmitted data is prevented.

[0011] An exemplary embodiment of the invention is explained in more detail below on the basis of the diagram.

[0012] The diagram shows:

[0013]FIG. 11: a block diagram for schematic representation of the major functional units involved in the method in accordance with the invention;

[0014]FIG. 22: a block diagram for schematic representation of a typical message TAN1; and

[0015]FIG. 33: a block diagram for schematic representation of a typical confirmation TAN2.

[0016]FIG. 1 shows a block schematic of an Intranet of a first unit Company A and an Intranet of a second unit Company B. The two Intranets are connected to each other by the publicly accessible Internet. Intranet in this case is taken to mean a local computer network in which accesses to the network originating from a network-external installation are only possible with an appropriate access authorization.

[0017] A data server S-D is located in the Intranet of the first unit Company A through which the data or services for internal users of the Intranet—not shown in the diagram—are provided. For access to the data or services of the data servers S-D originating from an external user device—i.e. in the present exemplary embodiment originating from the Intranet of the second unit Company B or originating from the Internet—it is necessary for the user to be authenticated as authorized before access.

[0018] The figure shows a user device C and a source server S-Q which are both located in the Intranet of the second unit Company B. Access to the data or services of the data server S-D originating from the external user device C will in this case be initialized by activating a link to a browser B running on a user device C. Instead of setting up a direct connection to the data server S-D, in accordance with the invention, in a first step S1 a connection is established to the source server S-Q and on the source server S-Q a connection module M-CON is activated.

[0019] In a second step S2 the connection module M-CON then sends a message TAN1 over the Internet to a destination server S-Z located in the Intranet of the first unit Company A. The message TAN1 in this case contains a unique identification SessionID. The connection module M-CON ensures here that the identification SessionID is unique and one-off, i.e. that the identification SessionID is only valid for what is referred to as a session. With the receipt of the message TAN1 a storage module M-STO is activated on the destination server S-Z. Message TAN1 is transmitted over the Internet in this case on the basis of the familiar HTTPS protocol. In addition message TAN1 is encrypted before its transmission by the connection module M-CON. The familiar PGP (PGP: Pretty Good Privacy) procedure is typically used for encryption. In this case message TAN2 will be encrypted with a public key assigned to storage module M-STO.

[0020]FIG. 2 shows a schematic diagram of a typical message TAN1. Message TAN1 includes a specific CompanyID for the second unit Company B of the connection module M-CON and the SessionID already mentioned above. The SessionID identification is typically a 64-bit integer. After the SessionID there is a time identifier TANCreationTime which for example specifies the number of milliseconds which have elapsed since 01.01.1970 up to the point of creation of message TAN1. Finally message TAN1 includes a TANExtension which is typically generated by a random number.

[0021] Reference is again made to FIG. 1. below In cases in which the message TAN1 can be decrypted by storage module M-STO using a private key assigned to the storage module M-STO and the identification SessionID is recognized as valid, the identification SessionID is stored along with period of validity information in a database DB located in the Intranet of the first unit Company A. The period of validity information specifies in this case for how long the data transferred in the confirmation is valid.

[0022] In cases in which the Session ID identification is recognized as invalid, and error message is returned in a step S3 to the connection module M-CON. In cases in which the Session ID identification is by contrast recognized as valid, a confirmation message TAN2 is returned in a step S3 to the connection module M-CON. The confirmation message TAN2 is again transmitted over the Internet in this case on the basis of the HTTPS protocol. In addition confirmation message TAN2 will be encrypted before transmission by storage module M-STO. The PGP procedure is again used as encryption procedure. Here confirmation message TAN2 will be encrypted with a public key assigned to connection module M-CON. Connection module M-CON can decrypt the received confirmation message TAN2 using a private key assigned to the connection module M-CON.

[0023]FIG. 3 shows a schematic diagram of a typical confirmation message TAN2. Confirmation message TAN2 comprises two parts. The first part includes an address information URL with which the data or services of data server S-D can be accessed. The second part corresponds to message TAN1 or contains a SessionID identification created by storage module M-STO constructed in accordance with unique and similar principles which can be uniquely assigned by connection module M-CON to the message TAN2 created there. For example the confirmation message TAN2 could have the following form:

[0024] https://www.firma-a.com/servlet/M-CHE?RequestID=5634636&Comp anyID=Company-a&SessionID=23497278&TANCreationTIME=293478293& TANExtension=29347293439

[0025] The fact that the current address information URL required for access to data server S-C is transmitted in confirmation message TAN2 to connection module M-CON means that a user does not have to know the address information URL before a data access. In addition the address information URL can be changed in any way required in the first unit Company A.

[0026] Reference is again made to FIG. 1. below If connection module M-CON has received and decrypted a confirmation message TAN2, in a step S4, controlled by connection module M-CON, a page is output on browser B of user device C containing the address information URL in the form of a link.

[0027] When the link is called a connection is established in a step S5 via the Internet to data server S-D and a checking module M-CHE is started on data server S-D. The checking module M-CHE checks the SessionID identification transferred during the connection setup against the SessionID identification stored in the database DB. If the check on the SessionID identifications delivers a positive result and if the period of validity of the identification ID has not yet expired, in a sixth step S6 a connection between the user device C and the data server S-D will be established over the Internet so that subsequently access originating from the external user device to the data and services of data server S-D is possible. Data is again transmitted over the Internet between user device C and data server S-D on the basis of the HTTPS protocol.

[0028] The SessionID identification is only valid for a one-off connection setup with checking module M-CHE. A further connection setup with data server S-D originating from an external user device with the same identification SessionID is no longer possible, i.e. the identification SessionID is no longer classified as valid for the second data access. This allows a subsequent access by an unauthorized user who has subsequently obtained knowledge of the SessionID identification to be suppressed.

[0029] Use of the HTTPS protocol ensures that so-called “eavesdropping” of the data transmitted in the Internet is prevented. The additional encryption of the data with the public keys of the connection module M-CON and the storage module M-STO additionally makes “eavesdropping” of the data transmitted in the Intranets of the first and second unit Company A, Company B impossible.

[0030] Connection module M-CON, storage module M-STO and checking module M-CHE are advantageously realized as what are known as “Servlets° i.e. they are applications running on the relevant servers—the source server S-Q, the destination server S-Z and the data server S-D—but are controlled by entries made in browser B of user device C.

[0031] In the present exemplary embodiment all users of the Intranet of the second unit Company B have access to the source server S-Q or to the connection module M-CON running on source server S-Q. This defines the restricted group of people for access to the data or services of data server S-D by the users of the Intranet of the second unit Company B. Alternately provision can also be made for the source server S-Q to be located in the Internet—accessible to all users—whereby in this case a self-contained group of users is defined for access to connection module M-CON in source server S-Q.

[0032] The method in accordance with the invention has the advantage that no authorized user administration is required in data server S-D so that access rights for the users do not have to be notified to the first unit Company A. A user accesses the data or services of data server S-D is therefore anonymous as far as the first unit Company A is concerned. A further advantage of the method in accordance with the invention is that a user of the authorization preceding the access to the data or services does not acquire any knowledge of it. The method in accordance with the invention is thus shown to be very user-friendly. 

1. Method for secure transmission of information between a user device (C) and a central computing device (S-D) located in a self-contained network, characterized in that originating from the user device (C) a request to connect with the central computing device (S-D) is sent to a second computing device (S-Q) not located in the self-contained network, that the second network device (S-Q) transmits a message (TAN1) containing a unique identification (SessionID) to a third computing device (S-Z) located in the self-contained network, that in cases in which the identification (SessionID) is recognized as valid, the third computing device (S-Z) stores the identification (SessionID) in a database (DB) and returns a confirmation message TAN (TAN2) to the second computing device (S-Q), that the user device (C) uses information contained in the confirmation message (TAN2) to initialize a connection with the central computing device (S-D), whereby the connection through the central computing device (S-D) is only accepted in cases in which access by the user device (C) is recognized from the stored identification (SessionID) as authorized.
 2. Method according to claim 1, characterized in that the confirmation message (TAN2) contains address information (URL) for data access to the central computing device (S-D).
 3. Method according to claim 1 or 2, characterized in that the connection request is signaled by a call, originating from a browser B running on the user device (C) to a connection module (M-CON) running on the second computing device (S-Q).
 4. Method according to claim 3, characterized in that access to the connection module (M-CON) is only possible for a restricted, authorized group of people.
 5. Method in accordance with one of the previous claims characterized in that the second computing device (S-Q) and the user device (C) are located in a further closed network.
 6. Method according to claim 3 or 5, characterized in that the connection module (M-CON) transmits the identification (SessionID) to a storage module (M-STO) running on the third computing device, and that in cases in which the identification (SessionID) is recognized as valid, the storage module (M-STO) stores the identification (SessionID) in a database (DB) and returns the confirmation message (TAN2) to the connection module (M-CON).
 7. Method according to claim 6, characterized in that data is transmitted between the connection module (M-CON) and the storage module (M-STO) in accordance with the familiar HTTPS protocol (HTTPS: HyperText Transport Protocol Secure).
 8. Method according to claim 6 or 7, characterized in that data is transmitted encrypted between the connection module (M-CON) and the storage module (M-STO).
 9. 2) Procedure in accordance with one of the claims 2 to 8, characterized in that the address information (URL) controlled by the connection module (M-CON) is displayed as a link to the browser (B).
 10. Method according to claim 9, characterized in that when the link is called at a user device (C) a checking module (M-CHE) is executed on the central computing device (S-D) and information containing the identification (SessionID) is automatically transferred to the checking module (M-CHE).
 11. Method according to claim 10, characterized in that in cases in which the identification transferred (SessionID) is identified as valid by the identification (SessionID) stored in the database (DB) a connection is established between the browser (B) and the checking module (M-CHE), and in cases in which the identification transferred (SessionID) is identified as invalid, an error message is transmitted by the checking module (M-CHE) to the browser (B)
 12. Method according to claim 10 or 11, characterized in that Data is transmitted between the browser (B) and the checking module (M-CHE) in accordance with the HTTPS protocol.
 13. Method in accordance with one of the previous claims characterized in that the identification (SessionID) is valid for a limited time.
 14. Method in accordance with one of the previous claims characterized in that the identification (SessionID) is only valid for one connection setup. 